A culture of microorganisms, such as microalgae and cyanobacteria, may change composition (e.g., proteins, lipids, pigments) and stages (e.g., growth, lipid accumulation) due to a plurality of culture parameters providing input to the cell. Examples of parameters of a microorganism culture which may change during the culturing period comprise, light exposure, pH, gas levels, nutrient levels, and temperature, which may affect the composition on a cellular level and culture level, such as density of the microorganisms, health of the microorganisms, life stage of the microorganisms (e.g., growth, lipid accumulation), culture composition (i.e. different types of microorganisms, organic materials, inorganic materials), and contamination level (e.g., predators, competing species, toxins, excreted products, bacteria, fungi). If one or more of the culture parameters fall below or rise above an optimal range, the microorganisms may perish, experience a decline in growth, or limit production of target products such as lipids, pigments, and proteins. In a commercial production setting, even small effects of the culture parameters outside of an optimal profile may result in losses due to decreased yield and increased costs.
For example, photosynthetic microorganisms use the energy provided by light in conjunction with carbon dioxide to produce chemical energy that is usable by the microorganisms for various cellular activities. Light of different wavelengths will affect the photosynthetic microorganism activities in different manners, including inhibiting activities in some instances. For example, light in the red wavelength spectrum (about 620-750 nm) may promote growth and cell division, while large amounts of light in the blue wavelength spectrum (about 450-495 nm) may lead to a loss in electron transfer in photosystem II of the cell and require repairs to photosystem II. Some wavelengths of light may even kill microorganisms if applied at the proper intensity and for the proper duration. In typical outdoor conditions where photosynthetic microorganisms receive solar energy, the photosynthetic microorganism is exposed to a wide variety of light wavelengths, some of which can cause photoinhibition and heating of the culture. Using the example of how light may affect photosynthetic microorganisms, the application of light may be used to control some of the conditions of a culture. However, the complex relationships between culture parameters can cause multiple parameters to change when a single parameter, such as light intensity, is applied to a culture.
For instance, a change in light intensity may increase the growth activity driven by photosynthesis may also affect the temperature and pH due to increased carbon dioxide consumption which may produce a negative effect on the microorganisms. With the potential for culture parameters to change quickly, and a culture may need to be monitored closely enough for corrective action to be taken before the culture is beyond a point of recovery. The ability to teach a system to learn and adapt continuously can make the difference between a culture of microorganisms perishing (resulting in a complete loss), and a productive harvest of the microorganisms. Conventional bioreactor systems are focused on a single task, which is typically growth, and may be designed specifically for parameters preferred by a single species or type of microorganism. The lack of flexibility of conventional bioreactors to continuously monitor a culture for adaptation, or to adjust to different parameters preferred by a different species or type of microorganisms leads to inefficient production.
Therefore, there is a need in the art for systems and methods to continuously monitor and control the parameters of a microorganism culture to maintain a culture profile optimized for a target characteristic, such as health, longevity, or production of a particular product.